The goal of this project is to develop clinical grade serum-free reagents for megakaryocyte proliferation and differentiation. This will permit novel hematopoietic rescue techniques for disorders such as thrombocytopenias. Preliminary data indicate that culture of CD34+ cells in the investigators' serum-free medium outperformed currently available alternatives. The proposed reagents will be optimized with regard to cytokines, culture times and other parameters. In addition to clinical applications, the reagents will enable the standardization of ex vivo protocols in laboratories. PROPOSED COMMERCIAL APPLICATION: Develop a clinical grade serum-free medium that will support the proliferation/differentiation of megakaryocytes/platelets for reinfusion into patients. Such a technology will be invaluable in fighting diseases/ infections and in coagulation.